The present invention relates to a process for bringing about sealing between machine parts moveable relative to one another by means of a sealing part moveably held in one of the machine parts at alternating pressures.
For sealing along uninterrupted sealing surfaces, e.g. on the cylindrical surface of a reciprocating piston machine or the inner surface of the casing of a rotary piston machine, in known processes of this type the sealing part is permanently pressed against the sealing surface by spring tension, although in the case of machines with pressures of the medium to be sealed which change down to vacuum level, a permanent, complete approximation of the sealing part or a contact pressure is not necessary. The pressure of the sealing part leads to friction losses and the stripping of lubricating fluid from the sealing surface.
For bringing about sealing by means of sealing or packing strips on rotary piston machines with uninterrupted sealing surfaces, it has already been proposed to mount the sealing strips in their centre of gravity. However, as they are pressed against the sealing surface, they move outwards somewhat at the interruptions of said surface, so that when again in contact with a sealing surface mechanical stresses occur or a complicated mechanical control of the sealing strips is necessary (U.S. Pat. No. 4,296,936).